Throttle valves for pneumatic tools or the like



K. G. KARDEN June 7, 1960 THROTTLE VALVES FOR PNEUMATIC TOOLS OR THE. LIKE Filed Jan. 3. 1955 2 Sheets-Sheet l 8 4 Z 9 Z A 2 P T N/ 5 /Iw/ b flu w. H m W m@ m w. m N S S Q M L m L K M 0 0 2 :7. 0 \\\\\W\\\\\\\\A 7 g H 9 d ,4 .4 J 6 6 l -|I\ |i MW w E u \\%-dr \\\y 5 25 My: M

June 7, 1960 K. G. KARDEN 2,939,675

THROTTLE VALVES FOR PNEUMATIC TOOLS OR THE LIKE Filed Jan. 3, 1955 2 Sheets-Sheet 2 INVEN TOR. AAm G'osrn KAQDs/v BY 3 M5 flTTOFPNEY THRO'ITLE VALVES FOR PNEUMATIC TOOLS 1 on'rnn LIKE? Karl Giista Kfirdn, Nacka, Sweden, assignfor to Atlas Copco Aktiebolag, a corporation of- Sweden FiIed Jan. 3, 1955, Ser. No. 479,578 Claims priority, application Sweden Jan. 12, 1954 Claims. (Cl. 251 -242) This invention relates to throttle valves for pneumatic tools or apparatus having a tubular valve member movable by means of a trigger or other operating means. Throttle valves for pneumatic tools and other compressed air driven apparatus usually forma part ofthe handle portion of the tool or the like.- Such, valves often comprise a cylindrical piston-valve-member which is guided and movable with an airtight fit in the handle portion or in a sleeve provided in the handle portion. Due to the accuracy with which such valves must be carried out in order to beperfectly tight such throttle valves are usually Throttle valves are also well known rather expensive. which comprise a mushroom type valve member provided on a stem having ducts axially .thereof. In such ,thro ttlea.

valves a bending of the airflow through the valve member and stem cannot be avoided and these valves are also. One.

rather expensive in manufacture and maintenance. object of this invention is to produce. aithrottle valve pro-.

Viding a substantially straight and unrestricted passage for the compressed air through the valve memberthereby with a minimum of grinding or lapping or similar 'expensive manufacturing processes. A further object of theinvention is'to provide adesign in which; the .valve member may bemanufactured from comparatively inexr pensive tubular stock. Further, features of the invention,

will be disclosed by the following specification and claims with reference tothe drawings,

In the accompanying, drawings four embodiments of throttle valves for pneumatic tools according to theinven tion are illustrated by way of example. Fig. 1 is a section through the'handle and motor-of a pneumatic tool. Figs.

2, 3 and 4 are sections through handle portions of pneumatic'tools provided with throttle valves according to three further embodiments of the invention. The invention may be. modified in various ways within thescope of the claims. I

In Fig. 1 1 designates the housing of a motor of a pneumatie tool and 2 a handle portion in which a throttle valve according to the invention is disposed. Compressed air may be supplied through a hose 3 which by means'of a suitable hose connection 4 is attached with screw threads at one end of the handle portion 2. Compressed air is conveyed through the throttle valve to a passage 5 in the handle and from said passage through an opening 6, the size of which is controlled by amemher 7 and a centrifugal governor 8, into an admission chamber 9 from which the "air is supplied to' the motor 10 which may, for instance, be a rotary vane motor the design of which is not described in detail since it has nothing to do with the invention.

A cylindrical bore 11 is provided inthe handle por- Fitenteddune 7, 196i? tion 2, as obvious from Fig; 1', and a tubular substantially cylindricalvalve members 12 is disposed in boreand axially movable therein by an operating means which in-this case consists of a trigger 13"; journalled'o'n a pin 13a-in the handle portion 2,- said trigger-havingfa finger 14-journalled on a pin- 14a in thetrigger'whichen gages a recess in thevvalve member formed by an ex.- ternal annular groove 15 in the valve-member 12. Oneachside of the groove-.15 thevalve-memb'er 12 has two annular grooves 16 and 17," respectively, in which an nular sealing rings'18 and"1-9,- respectively, for instance O-rings, ofrubber are provided. The-"sealing'singslS;

a is interposed between the valve member 12 anda bushing 19 cooperate with cylindrical surfaces'of the same diame ter in the bore-ll and prevent thc compressedairfrom' leaking out around the valve member through'anopening 20in thehandle pontion-2 in which the trigger 13 andfinger 14 are disposed. The valve-member 12 is pro vided with a straight passage 21' extendingcentrally and axially throughout the valve; member from one end to the other. Aplug 22 is secured in thehandle portion 2 and'carries a ring 23 of suitable packing material which forms a seat 24 fora sealingsurfa'ce 25'provided onan endface ofthe valve "member12. Thefsealing surface 25 is defined by -a tapering bore 26in the valve member whichmerges.into-the passagc 21. A helical spring27 28in the handle portion 2 whichbushi-ng' carries astrain-r er- '29.. In closed position the valve member' 12 is pressed against the seat 24 by the spring 27 andthe air pressureLin the supply conduit 3. When the; valve is opened thevalve memberis lifted from'its seat 2'4 by' means of-thc trigger v 13 and'thefinger 14:which"engages' an abutment 30='on-.the:valve" member. Compressed air then .flows fromthe conduit '3 throu'ghthe. straight passage zli'andtthen between the .sealingsurface 25- and the seati- 24 to an annular space SI inithezhandle portion 2'which cylindrical extehral. contourl'is very simple and cheap manufacture: and it is-also obvi'ousthat-the bore 11 in the l handleportion 12 -may be carried outlina simple way..-

Due to the arrangement of the sealing rings .-18',419.:c1ose': tolerances are notnecessaryon. the. outer :surface ofthe valvesmember; and thepsurfacepf the .bore' 11 and a large:

straight unrestricted passage is obtained through the valves member.=-. x V v In -.-the.fmodification f the invention illustrated in Fig. 2 5,32 designatesth handle portionv of -a:1 -compressed:.air-"i tool. Said handle portion isprovided withcoaxial 'bore'sr 33, 34 with slightly difierent diameters. 1 :A.-tubulau valve member 35 having portionswith corresponding-diameters is movable Qin thebores. 33; 34 and provided with sealing rings. 36.37;; :A; hose. connection 38:issecured-in one end-:2

big-the handle, portionp32. y axial -;jduct 39- :extends straight through the valve ;memb.er. 35f irom one end to the other. ,At'one end face thevalve member is provided :3,

a .sealing surface 61} ofanmilar shape which operates. with a vpacking 40 forming. a v'alve rom a char'nber 41 passages 42 lead to the working c amber ing. The air pressure on the big end of the valve membe urges the valve member in closing direction.

Fig. 3 illustrates a further modification of the invention. On a handle portion 46 of a tool or the like a sleeve 47 is secured by screw threads at one end of the r I 3 sleeve, which carries a hose connection 48 at the oppo: site end. A two-piece operating sleeve 49 is mounted to turn on the sleeve 47. The sleeve 49 has helical recesses or igroovesfi) whichqcooperatewith pins 51 fitted in lugs, on-a tubular valve' me'mberiz. The pins 51 are guided by straight axialgrooves-provided -in-the sleeye 47. A spring SS-forces the'valve member fiz against ea seat. formed ona packing 54 carried by the plugshaped end of thehandleportion 46. The sealing surface on the end face of the valve member -2 is designated by 64, Q-rings 55 and 56 areprovided in grooves in the hose connection;48;and the sleeve-47 and-cooperate with the external cylindrical surfaces of the valve member 52. The {valve member is provided with an axial passage 57 which extends straight through the valve member from one end to 'theotherr From a space5'8 passages 59,60 lead to the workingchamber of the tool or the like.

Ilurningof-the sleeve-49 in one direction causes; the valvcmembctSZ to bedispla'ced in-the bores-61,-'62 from theseat on the packing ring 54. The embodiment of the invention illustrated inFig. .3 is particularly adapted for toolshavinga smooth and straight handle portion;

In the embodiment of Fig. 4 the handle portion 70 haea. bore 71 communicating with theai'r consumingde-' vice-of 'a-t'ool' and a bone 72-fola tubular valve member 73 aswell asa-bore 74 for a plug 75 and a hose sconce-- tion' plug 761 The plug'75 carricsavalveseatofrubber 77 which is" vulcanized to" a head-78 carried-- by the plug 75.- A spring-79 urges the valve" member towards-the seat and a trigger 'Sfljournall'edon: a :pin 81* in: the" opening 82 has afinger' si' cooperati-ng' with an annula'r groove 84 totmove the valveme'mbe'r in the-direction-ofthe air flow; to open itag ainsf the pressure-of the spring: 79.

Q-rin'g's 85 form seals with the-wall of thebore 72-1211 venting-air fromleaking out through the opening 82. It-sh'ould'be observed-thatthethrotflevalve of Fig. 4 is substantially only an inversion of the throttle valve of Fig; l-- in so far opensin opposite directioifwith" regard to the direotion of 'the air flow.

The throttle valves above describedand illustrated the drawings should-onlybe considered as examples and may be modified in' several difie'rent "ways within the scope-of the claimsi The valve" of Fig. 3 may,;.for iiistance, be operated by a trigger similar to the trigger 43" of Fignfi and 'thedugs and: pins-51 may in eachcasebe replaeed -by" anarinular flange similar-to 'the" arrangement in Fig. 2; welded: to an otherwise straight and-smooth piece: of tube: Throttle valves"according to the' i'nvention' may" naturally be employed in- "any pneumatic" tool or apparatus in which it may be built in a suitable'iniam nere- The throttle valve -iac'cordingi-to' the" invention may beF uSEd'imrotating tools ra'swell: asin-Z hammer tools and other-compressed air driven apparatus.

What fclaim isz a-;-srair hr-unresnietea paaawrer cem ressea as mas ers 4 t tending from one end to the other internally of said valve member and freely movable in the bore from closed to open position and vice versa, an operating member for said valve member in said handle portion engaging the outside of the valve member, a valve seat in the handle portion at one end of the bore, a sealing surface on an endface of; the valve member formed for cooperation with said valve seat, and 0-1"ii1g packings around the valve member sealing between the valve member and the bore of 'the'hand'lefpofiionat 'eafc'h side' cf the po int of engagement of said operating member and the valve member. a

2. A valve structure according to claim 1, inwhich annular groovesare' provided in the external envelope surface of the valve member for accommodating the O-ring packings.

3. A valve structure according to claim 1, in which the valve member is' flared internally towards the end cooperatingwitli the valveseat. v

-4."Ih a' pneumatictool of apparatus havir'i'g arl elongatedhandle member, a' valve structure comprising a bore'extending longitudinally itrhr'oiigh said handle member andadaptd t'o comma-mare with a com'pre'ss'edair supply conduit at one ena and with a compressed air consuming eevi'ce in the tool or apparatus" at are 'opp'dsite end, a circumferentially continuous tubular valve meniber having a straight unrestricted passage for compressed air ext'ending from one'erid mine other internally of said valve member" and freely r'ncivablein the bore from closed to open-position and vice" versa, an operating me'mber for said valve member in said handle member engaging the outside'o'f the" valve" meniber, valve 1 means comprising" a sealing surface 'c'arr'ied'by said handle said elastic sealing surface constitutes "the valveseat car member atone end of said bore and acoop'e'r'atirig se'al5 in'g surface carried by said valve member at one end thereof and 'locatcii'to abut' said first-mentioned surface \vlieiisaid valve member is in said closed position, one

of said sealing surfaces being" elastic, said valve member having"longitudinallyrspaced circumferential grooves in the external cylindrical surface thereof, one of, ,said grooves being located on each sideof the point of engage'meiit of said opera-ting member with said valve mem her, and O-ring packings-located in each-of said-grooves for'provitiing' fiuid t ht seals' between said valve member and thef'wall of said'b'oreat either side of said point of engagement. V I V I p v 5. 'A valve structure according to" '4} in which ried-hy said'handleniem-ber. I

References cited inth'e fileofthispa'tefit" UNITED STATES PAT-ENTS' 

